Tissue segregation in the early vertebrate embryo

Fagotto, François

doi:10.1016/j.semcdb.2020.05.020

Cited by 18 publications

(19 citation statements)

References 141 publications

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“…Interestingly, such bisections revealed a concomitant lack of Brachet's cleft, implying incorrect tissue remodeling during early gastrulation ( Fig. 2 C-F; Fagotto, 2020 ). These phenotypes became more apparent when morphants were analyzed for notochordal noggin ( nog ) expression at mid/late gastrula stage, illustrating strongly impaired axial elongation and reduced nog expression itself, also indicating a failure in maintaining notochordal fates in morphant tissue ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Rab7 is required for mesoderm patterning and gastrulation in Xenopus

2021

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Early embryogenesis requires tightly controlled temporal and spatial coordination of cellular behavior and signaling. Modulations are achieved at multiple levels, from cellular transcription to tissue-scale behavior. Intracellularly, the endolysosomal system emerges as an important regulator at different levels – but in vivo studies are rare. In the frog Xenopus, little is known about developmental roles of endosomal regulators, or their potential involvement in signaling, especially true for late endosomes. Here, we chose to analyze a hypothesized role of Rab7 in this context, a small GTPase known for its role as a late endosomal regulator. First, rab7 showed strong maternal expression. Following localized zygotic transcript enrichment in the mesodermal ring and neural plate, it was found in tailbud stage neural ectoderm, notochord, pronephros, eyes and neural crest tissues. Inhibition resulted in strong axis defects caused by a requirement of rab7 for mesodermal patterning and correct gastrulation movements. To test a potential involvement in growth factor signaling, we analyzed early Wnt-dependent processes in the mesoderm. Our results suggest a selective requirement for ligand-induced Wnt activation, implicating a context-dependent role of Rab7.

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Section: Resultsmentioning

confidence: 99%

Rab7 is required for mesoderm patterning and gastrulation in Xenopus

2021

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“…Interestingly, bisections revealed a concomitant lack of Brachet's cleft, implying incorrect tissue remodeling during early gastrulation ( Fig. 2C-F; (Fagotto, 2020). These phenotypes became also apparent when such embryos were analyzed for notochordal noggin (nog) expression at mid-gastrula, supporting strongly impaired axial mesoderm elongation and reduced nog expression itself, the latter one indicating a failure in maintaining notochordal fates in morphant tissue ( Fig.…”

Section: Rab7 Is Required For Convergent Extension and Notochord Morpmentioning

confidence: 86%

Rab7 mediates Wnt-dependent mesoderm patterning and gastrulation inXenopus

Kreis

Wielath

Vick

2020

Preprint

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Early embryogenesis requires tightly controlled temporal and spatial activity of growth factors. Modulation is achieved at multiple levels, from cellular transcription to tissue-scale propagation, concerning activation, maintenance, or termination of signaling. Intracellularly, the endolysosomal system emerged as important factor for such regulations. Endocytosis and early endosomes mainly orchestrate activation and transduction of signals, while late endosomes are thought to mediate lysosome-based termination. Only few reports attributed activating roles to late endosomes, mainly for Wnt pathway activation. In Xenopus, few is known about developmental roles of endosomal regulators, or their function for signaling, especially true for late endosomes. Therefore, we chose to analyze a hypothesized positive role of Rab7 in this context, a small GTPase mainly known for its role as a late endosomal regulator. We analyzed if Rab7 participates in early activation of growth factor signaling, focusing on Wnt signaling. We found rab7 expressed very localized throughout development, and inhibition resulted in strong gastrulation defects. Concomitantly, Rab7 was strictly required for both, exogenous activation and endogenous Wnt-mediated patterning of the mesoderm.

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“…In the absence of this boundary, ectoderm and mesoderm cells start to intercalate, the two tissues fuse, mesoderm internalization stalls, and gastrulation aborts. The cellular mechanism responsible for maintenance of this boundary was recently identified (reviewed in [ 41 , 42 , 43 ]). It mainly relies on ephrin-Eph signalling across the tissue interface, which leads to bursts of local actomyosin contractility, temporarily destabilizing specifically ectoderm–mesoderm adhesive contacts.…”

Section: Epcam Function In Tissue Morphogenesismentioning

confidence: 99%

EpCAM as Modulator of Tissue Plasticity

Fagotto

2020

Cells

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The Epithelial Cell Adhesion Molecule or EpCAM is a well-known marker highly expressed in carcinomas and showing a strong correlation with poor cancer prognosis. While its name relates to its proposed function as a cell adhesion molecule, EpCAM has been shown to have various signalling functions. In particular, it has been identified as an important positive regulator of cell adhesion and migration, playing an essential role in embryonic morphogenesis as well as intestinal homeostasis. This activity is not due to its putative adhesive function, but rather to its ability to repress myosin contractility by impinging on a PKC signalling cascade. This mechanism confers EpCAM the unique property of favouring tissue plasticity. I review here the currently available data, comment on possible connections with other properties of EpCAM, and discuss the potential significance in the context of cancer invasion.

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Tissue segregation in the early vertebrate embryo

Cited by 18 publications

References 141 publications

Rab7 is required for mesoderm patterning and gastrulation in Xenopus

Rab7 is required for mesoderm patterning and gastrulation in Xenopus

Rab7 mediates Wnt-dependent mesoderm patterning and gastrulation inXenopus

EpCAM as Modulator of Tissue Plasticity

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